A semiconductor device includes a wiring substrate on which semiconductor elements are mounted. When the semiconductor element (i.e., semiconductor chip) includes a circuit for a high frequency such as the milliwave band, an antenna is connected to the high frequency circuit. The antenna is connected to the semiconductor element by a bonding wire. Japanese Laid-Out Patent Publication No. 2011-114192 describes one example of a wiring substrate including an antenna. In the wiring substrate, the semiconductor element and the bonding wire are covered by a recessed cap which is adhered to the wiring substrate.